In 1919, German crews sank their own fleet at Scapa Flow. 100 years later, its steel became prized by industry for being radioactive-free

History sometimes gives old objects an unexpected second life.

In the summer of 1919, a remarkable event unfolded beneath the waters of Scapa Flow, a sheltered body of water in Scotland's Orkney Islands. German sailors deliberately sank much of their country's surrendered naval fleet rather than allow the vessels to be divided among the victorious Allied powers.